Activation of the umami taste receptor (T1R1/T1R3) initiates the peristaltic reflex and pellet propulsion in the distal colon

Takashima

et al. 2017

Developmental Biology

Entero-endocrine cells involved in the regulation of digestive function form a large and diverse cell population within the intestinal epithelium of all animals. Together with absorptive enterocytes and secretory gland cells, entero-endocrine cells are generated by the embryonic endoderm and, in the mature animal, from a pool of endoderm derived, self-renewing stem cells. Entero-endocrine cells share many structural/functional and developmental properties with sensory neurons, which hints at the possibility of an ancient evolutionary relationship between these two cell types. We will survey in this article recent findings that emphasize the similarities between entero-endocrine cells and sensory neurons in vertebrates and insects, for which a substantial volume of data pertaining to the entero-endocrine system has been compiled. We will then report new findings that shed light on the specification and morphogenesis of entero-endocrine cells in Drosophila. In this system, presumptive intestinal stem cells (pISCs), generated during early metamorphosis, undergo several rounds of mitosis that produce the endocrine cells and stem cells (ISCs) with which the fly is born. Clonal analysis demonstrated that individual pISCs can give rise to endocrine cells expressing different types of peptides. Immature endocrine cells start out as unpolarized cells located basally of the gut epithelium; they each extend an apical process into the epithelium which establishes a junctional complex and apical membrane specializations contacting the lumen of the gut. Finally, we show that the Drosophila homolog of ngn3, a bHLH gene that defines the entero-endocrine lineage in mammals, is expressed and required for the differentiation of this cell type in the fly gut.

Section: Introductionmentioning

confidence: 88%

bHLH proneural genes as cell fate determinants of entero-endocrine cells, an evolutionarily conserved lineage sharing a common root with sensory neurons

Takashima

et al. 2017

Developmental Biology

“…Video recording and spatiotemporal mapping of intestinal and colonic segments have been applied to a variety of species including zebrafish 26 , mouse 25,[27][28][29][30] , rat 7,9,[30][31][32][33] , guinea pig 5,6,8,[13][14][15][16][17][18][19]24,30,32,34,35 , brushtail possum 12,36 , rabbit 2,30,37,38 , chicken 39 , pig 40,41 and human 42 . The most widely studied species is the guinea pig.…”

Section: Discussionmentioning

confidence: 99%

“…The construction of STmaps and analysis of changes in motility pattern have been applied to key questions in the gastrointestinal motility of intestine and colon. These include: differentiation of neurogenic and myogenic contractions and defining the role of interstitial cells of Cajal 6,9,11,12,16,24,26,27,[29][30][31]33,[37][38][39][40]42 , understanding the complex interactions between the circular and longitudinal muscle layers 2,7,8,11,12,32,39,40 , examining the effects of intraluminal nutrients 10,18,19 , microbial strains 34 , and viscosities 12,36 on various motility patterns, and understanding the role of various endogenous neurohormonal agents and exogenous pharmacological agents 2,[4][5][6][7]9,10,[13][14][15][16][17]28,35,40 in the generation and modification of motility...…”

Section: Discussionmentioning

confidence: 99%

“…While many groups have generated their own software packages or plugins, they all analyze diameters of a tissue segment and convert those various diameters to grayscale representation. A commercially available recording and analysis system called the GastroIntestinal Motility Monitoring system (GIMM) provides a turnkey approach that allows for analysis of both propulsive motility via fecal pellet velocity determination in the guinea pig distal colon 13 as well as analysis of propulsive and mixing motility patterns with a fluid stimulus in intact intestinal segments 4,5,[14][15][16][17][18][19] 4. General Experimental Procedures 1.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spatiotemporal Mapping of Motility in <em>Ex Vivo</em> Preparations of the Intestines

Kendig

Hurst

Grider

2016

JoVE

Self Cite

Multiple approaches have been used to record and evaluate gastrointestinal motility including: recording changes in muscle tension, intraluminal pressure, and membrane potential. All of these approaches depend on measurement of activity at one or multiple locations along the gut simultaneously which are then interpreted to provide a sense of overall motility patterns. Recently, the development of video recording and spatiotemporal mapping (STmap) techniques have made it possible to observe and analyze complex patterns in ex vivo whole segments of colon and intestine. Once recorded and digitized, video records can be converted to STmaps in which the luminal diameter is converted to grayscale or color [called diameter maps (Dmaps)]. STmaps can provide data on motility direction (i.e., stationary, peristaltic, antiperistaltic), velocity, duration, frequency and strength of contractile motility patterns. Advantages of this approach include: analysis of interaction or simultaneous development of different motility patterns in different regions of the same segment, visualization of motility pattern changes over time, and analysis of how activity in one region influences activity in another region. Video recordings can be replayed with different timescales and analysis parameters so that separate STmaps and motility patterns can be analyzed in more detail. This protocol specifically details the effects of intraluminal fluid distension and intraluminal stimuli that affect motility generation. The use of luminal receptor agonists and antagonists provides mechanistic information on how specific patterns are initiated and how one pattern can be converted into another pattern. The technique is limited by the ability to only measure motility that causes changes in luminal diameter, without providing data on intraluminal pressure changes or muscle tension, and by the generation of artifacts based upon experimental setup; although, analysis methods can account for these issues. When compared to previous techniques the video recording and STmap approach provides a more comprehensive understanding of gastrointestinal motility. Video LinkThe video component of this article can be found at

Biochemical and Biophysical Research Communications

“…The activation of T1R1/T1R3 expressed in the colon elicits the peristaltic reflex and pellet propulsion in mammals [24]. In regard to the gastrointestinal mGluRs, Akiba et al reported that mGluR1 and mGluR4 expressed in the duodenum regulate the duodenal mucosal defense to acidic stimulus [25].…”

Section: Discussionmentioning

confidence: 99%

Expressions of multiple umami taste receptors in oral and gastrointestinal tissues, and umami taste synergism in chickens

Yoshida

Kawabata

et al. 2015

Umami taste is one of the five basic taste qualities, along with sweet, bitter, sour, and salty, and is elicited by some l-amino acids and their salts, including monopotassium l-glutamate (MPG). The unique characteristic of umami taste is that it is synergistically enhanced by 5'-ribonucleotides such as inosine 5'-monophosphate (IMP). Unlike the other four basic taste qualities, the presence of umami taste sense in avian species is not fully understood. In this study, we demonstrated the expression of multiple umami taste receptor candidates in oral and gastrointestinal tract tissues in chickens using RT-PCR analysis. We first showed the metabotropic glutamate receptors (mGluRs) expressed in these tissues. Furthermore, we examined the preference for umami taste in chickens, focusing on the synergistic effect of umami taste as determined by the two-feed choice test. We concluded that chickens preferred feed containing both added MPG and added IMP over feeds containing either added MPG or added IMP alone and over the control feed. These results suggest that the umami taste sense and synergism are conserved in chickens.